Centeral nervous system shunt monitoring system

ABSTRACT

A method of monitoring Central Nervous Shunt performance by sampling non-invasive data from a patient with hydrocephalus condition. The sampled data is processed to produce a determination of probable shunt operation. Where the shunt may not operate properly, the processing produces a prediction of possible shunt malfunction. The processing includes a method to assess which of a set of possible malfunctions is the most likely. The processing can also be used to advise the user on how to remedy the problem diagnosed. The shunt performance rating can also be used to monitor shunt performance over time and process the time data to provide for a shunt operation status or observe the compatibility of a particular shunt type to a patient.

RELATED APPLICATION

[0001] This application is a divisional of prior application Ser. No.09/197,125, filed Nov. 20, 1998.

FIELD OF THE INVENTION

[0002] This invention relates to a system for monitoring a shuntperformance for patients with a hydrocephalus condition.

BACKGROUND OF THE INVENTION

[0003] Hydrocephalus comes from the Greek: hydro means water, cephalusmeans head. Hydrocephalus is an abnormal accumulation offluid—cerebrospinal fluid (“CSF”) within cavities called ventricles,inside the brain. CSF is produced in the ventricles, circulates throughthe ventricular system, and is absorbed into the bloodstream. CSF isreabsorbed at a rate that is dependent on regulation of intracranialpressure (“ICP”). CSF is in constant circulation and has many importantfunctions. It surrounds the brain and spinal cord and acts as aprotective cushion against injury. CSF contains nutrients and proteinsthat are needed for the nourishment and normal function of the brain. Italso carries waste products away from surrounding tissues. Hydrocephalusoccurs when there is an imbalance between the amount of CSF that isproduced and the rate at which it is absorbed. As the CSF builds up, itcauses the ventricles to enlarge and the pressure inside the head toincrease. Congenital Hydrocephalus is thought to be caused by a complexinteraction of genetic and environmental factors. Aqueductal stenosis,an obstruction of the cerebral aqueduct, is the most frequent cause ofcongenital hydrocephalus. Acquired hydrocephalus may result from spinabifida, intraventricular hemorrhage, meningitis, head trauma, tumors andcysts. Hydrocephalus affects about one in every 500 children born.

[0004] There is no known way to prevent or cure hydrocephalus. To date,the most effective treatment is surgical insertion of a shunt. A shuntis a flexible tube placed into the ventricular system of the brain whichdiverts the flow of CSF into another region of the body, most often theabdominal cavity or a chamber of the heart, where it can be absorbed. Avalve within the shunt attempts to maintain the CSF at a pre-estimatedICP by allowing the valve to open in response to that pressure level.Under most circumstances, no specific testing is performed in advance ofsurgery to try and estimate the patient's flow needs. Since the flowneeds are not determined prior to the insertion of the shunt, moresurgery may be necessary in the future to fit a matching valve for thepatient.

[0005] A shunt is simply a drain, which diverts the accumulated CSF fromthe obstructed pathways and returns it to the bloodstream. The deviceconsists of a system of tubes with a valve to control the rate ofdrainage and prevent back-flow. It is inserted surgically so that theupper end is in a ventricle of the brain and the lower end leads eitherinto the heart (ventriculo-atrial, FIG. 2A) or into the abdomen(ventriculo-peritoneal, FIG. 2B). The device is completely enclosed sothat all of it is inside the body. Other drainage sites such as theouter lining of the lungs (ventriculo-pleural shunt) can also be used.In most cases, the shunts are intended to stay in place for life,although alterations or revisions might become necessary from time totime.

[0006] Today, there are numerous types of shunts but while different inappearance they work in a very similar manner. None can be said to besignificantly better or worse than others, and the shunt is usuallychosen by the surgeon based on experience, cost and personal preference.Special in-hospital 24-hour monitoring can be utilized to evaluate thedegree of shunt dependency and ICP requirements. The hospital monitoringis expensive, complicated, and is usually only a last resort effort whenthe patient condition is quite severe.

[0007] Originally, shunts were inserted so that a tube drained CSF fromthe ventricles in the brain, through the valve and through another tubeinto a vein in the neck and then into the heart (FIG. 2A). While theseare still used, most currently drain the CSF into the abdomen (FIG. 2B)and the bottom tube can be felt over the ribs. Despite all thesedevelopments, shunting can have complications. These can be divided intounder-drainage, over-drainage and infection. The treatment involvesoperations, often indeterminate hospital stays and disappointingrelapses before a successful outcome could eventually be realized. Thereis a need for a way to monitor hydrocephalus patients during their dailyroutines after having a shunt implantation as to better evaluate theperformance of the shunt and valve matching for the patient.

SUMMARY OF THE INVENTION

[0008] In accordance with the invention there is provided a CentralNervous System (“CNS”) Shunt Monitoring System, referred to as “DiaCeph™Test,” which is a home and physician office monitoring system forhydrocephalus patients with CNS shunts. The DiaCeph™ Test evaluatesspecific neurological findings of the hydrocephalus patient, processesit with a special unit, introduces specifically tailored interventions,and results in a specific diagnosis. The system provides for astandardization for communicating the performance of a shunt. While inthe past patients struggled to communicate the symptoms they areexperiencing to a doctor, with the DiaCeph™ monitoring system, thecommunication is effortless. The system can either directly communicatewith a doctor's computer or generate a printout of the observations fora doctor to review.

[0009] The DiaCeph™ Shunt Monitoring System can be described in fourparts. First, the user evaluates and scores real-time sets of patientdata. Next, the data is processed in the DiaCeph™ processor. Theprocessor carries out a series of steps and calculations whereby thepatient's data is analyzed and coded. It employs proprietarycalculations as it considers the possible shunt scenarios, and renders aspecific diagnosis from a list of shunt malfunctions. Next, thepatient's data is plotted on a chart. The chart serves as a means formonitoring “live” patient data over the course of time. This is comparedto the patient's pre-established normal, and to a DiaCeph™ Standard. Thefinal part is the Advanced DiaCeph™ Test. Here specific non-invasiveInterventions or manipulations are used to explore a complex diagnosis.The Slide Chart or processor chooses the Interventions, any to avoid,and confirms or rejects the diagnosis. These Interventions also helpmanage many common hydrocephalus complaints.

[0010] The DiaCeph™ Test will assist the physician in determining if apatient is experiencing a malfunction necessitating costly hospital careand testing, a matter of importance in today's insurance market. It willserve families with the benefits of a proven test product for evaluatingcomplaints in the home. It could become a standard in hydrocephalusresearch.

[0011] Routine use of the DiaCeph™ Test will reduce exploratory testingand dependence on emergency room treatment, and provide the shuntedpatient and his/her family with increased independence in the homesetting. The ability to track real time shunt performance will no doubtlead to improved care and treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1A is a flowchart illustrating the operation of some part ofthe DiaCeph™ system;

[0013]FIG. 1B is a flowchart illustrating the operation of parts of theDiaCeph™ system following those in FIG. 1A;

[0014]FIG. 2A is an illustration of a Ventriculo-Atrial shunt;

[0015]FIG. 2B is an illustration of a Ventriculo-Peritoneal shunt;

[0016]FIG. 3 is an example of the DiaCeph™ monitoring work page used tocollect data concerning a patient;

[0017]FIG. 4 is an example of a chart tracking shunt performance overthe course of one day;

[0018]FIG. 5 is an example of a first template of the DiaCeph™processor;

[0019]FIG. 6 is an example of a second template of the DiaCeph™processor;

[0020]FIG. 7 is an example of a third template of the DiaCeph™processor;

[0021]FIG. 8 is an example of a fourth template, includinginterventions, of the DiaCeph™ processor;

[0022]FIG. 9 is an illustration of the components of an apparatus toperform the method of the present invention;

[0023]FIG. 10 is an illustration of a shunt valve with a reservoir,proximal, and distal occluders;

[0024]FIG. 12 is an illustration of the distal patency check testingprocedure for the shunt of FIG. 10;

[0025]FIG. 11 is an illustration of a shunt reservoir with nodirectional occluders; and

[0026]FIG. 13 is an illustration of the shunt reservoir finger testingprocedure for the shunt of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0027] With reference to FIG. 1, the steps taken by a system inaccordance with the method of the present invention will be illustrated.First, the user selects options from a start menu 101. Some of theoptions that can be available are a journal review, download data to PC,conduct tests, set-up preferences, review user instructions, or createcustom files. The user should select a shunt type from the list of shunttypes available. The user can also select a test profile to conductother than the default profile. The test preference will usually berecommended by a doctor or other treating party. The user may alsoselect a desired cognitive test at this time such that the samecognitive test is performed each time a sample data is taken.

[0028] Once all the information concerning the patient is entered, thesystem will either prompt the user to conduct the specific test ordirect the user to a list of tests to perform that is applicable to theinformation entered. Once the user selects the “conduct tests” entry thesystem prompts the user to choose a test type 102 from a standard oradvance single sample test 105, a pre-set timed standard 104 or advancesampling 103 (a set of samples over a predefined time period). Thestandard sampling will proceed in accordance with a pre-selectedpreference test profile. In the example shown preference A 106 wasselected. The preference includes an activity 107, nausea 108, Headache109, malaise 110, and cognitive scoring 112. Additionally the preferenceincludes both positional tests 113, the supine 114, and upright 115positions. All data from the scoring and positional tests is transferredto both the journal 119 and the ICP processor 117. The journal 119 isused to store the observations for later review or processing. The ICPprocessor 117 in the example shown, uses a barometric pressure sensor116 in estimating the ICP. The processor 117 then sends the ICP to theoutput unit 118. The output unit 118 transmits the ICP to the diagnosticprocessor 120.

[0029] In FIG. 1B, the steps following those in FIG. 1A are illustrated.The next sample is that of the shunt tract 121. The observation of theshunt tract 121 is followed by a proximal patency 122, proximal refill123, distal patency 124, and distal refill 125 observations. Theobservation data is transmitted to the journal 119 and the diagnosticprocessor 120. The diagnostic processor 120 uses the observations,barometric pressure data, and shunt type information to generate adiagnosis 126.

[0030] Once a diagnosis is generated the user can choose whether to endthe test and return to the menu 101, perform the advanced portion of thetest 131, or take another sample 130. The advanced portion of the test131 will take the user to the intervention processor 133 which willgenerate a set of interventions to perform. If there are interventionsto perform, the answer in step 134 will be yes. The user will thenperform the intervention 135 and determine its outcome 136. The outcomeis passed back to the intervention processor 133 for further analysis.Once all recommended interventions are performed the user will beprompted back to the menu 101. A computerized unit that prompts the userto conduct tests and enter results can greatly simplify the data entryprocedure. The description below includes the details of some of thesteps in FIGS. 1A and 1B with reference to the later Figures.

[0031] Step 1. Time and Nausea Measurements. Write down the time of daynext to the sample under “Time” on the work page of FIG. 3. List anyactivity or medical event that preceded the hydrocephalus incident beinginvestigated under “Activity/Event.” It might be a fever, headache orstare-like state upon awakening, or difficulty following an activity.Next, identify any Nausea or Vomiting by circling a representative scoreunder “Nausea.” Scoring: 3 severe vomiting and nausea; 2 moderate nauseawith some vomiting; 1 nausea only, may warrant medication orintervention.

[0032] Step 2. Identifying the Headache (HA). Identify the patient'sheadache as the worst degree of severity that was associated with thehydrocephalus incident in this test. If necessary, place the patient inthe incident position for several minutes. Circle the headache scorethat best corresponds to its severity under “Headache.” Scoring:N=normal, no HA; 1=moderate HA, but tolerable, may or may not medicate,often able to continue activities; 2=moderately severe HA, requiresmedication, often requires lying down, no activity, may include nauseaor vomiting; 3=severe HA, requires strong medication, stop allactivities, rest, likely vomiting.

[0033] A “malaise” score (not on chart in FIG. 3, but mentioned in theflow chart of FIG. 1) may be prompted under certain test preferences.Malaise can be best described as a debilitating feeling regardingstamina and health, often shown as weakness. The user should identifythe score that best describes the conditions. The possible scores canbe, for example, N=normal; 1=moderate, but tolerable feeling ofweakness, may affect but not prevent activities; 2=moderately severelevel where many common activities are not possible; 3=severe, bedridden and confined.

[0034] Step 3. The Shunt/Reservoir Evaluation. The first portion of thistest involves a physical examination of the shunt valve and cathetertract. Start where the ventricular catheter exits the skull. Check theshunt valve, connectors, and distal catheter by running your fingersalong the patient's shunt tract. Look for signs of fluid accumulationand focal pain. If necessary, have the patient hold their breath as youinspect the chest and abdomen. If unsure of the findings, mark “NoPain/No Swelling” followed by a “?”. Identify findings under the ShuntTract column of FIG. 3 as: No Pain/No Swelling (No P/S), ProximalPain/Swelling (Prox. P/S), Proximal Pain/No Swelling, No Pain/ProximalSwelling, Distal Pain/Swelling, Distal Pain/No Swelling, No Pain/DistalSwelling. Abbreviate when needed.

[0035] The DiaCeph™ system provides, for example, two separate testmethods for performing the Shunt Reservoir Finger Test. The two methodscorrespond to two types of CNS shunt systems incorporating reservoirs,referred to here as Type 1 and Type 2 shunts. A selection of shunt typeat the start of the sampling procedure will direct the user to theproper test to perform for the selected shunt type.

[0036] Type 1 shunt systems (FIG. 10) consist of a differential pressureshunt valve with an integral central reservoir and proximal and distaldirectional occluders on each side of the valve. The system terms itsreservoir test method for this shunt as Method 1 (FIGS. 10/12). Type 2shunt systems (FIG. 11) employ an In-Line reservoir without theoccluders, and hence are not capable of selective flushing. Theapplicable test technique is termed Method 2 (FIGS. 11/13). It may beapplied to any CNS shunt that has a Percutaneous flushing reservoir. Itis important to verify the type of reservoir/shunt system so as toobtain the most reliable data possible from this test.

[0037] The DiaCeph™ method provides a sampling technique for Type 1systems, termed the “Two Finger Palpating Technique.” This techniqueemploys the index/middle fingers of the same hand to depress and samplethe reservoir. Other users may prefer to use the index or middle fingersof both hands to depress and sample the reservoir. The best techniquefor any given user is one that is comfortable to the user and can bereplicated in a reliable manner. Reservoir testing is best performed inthe Supine posture, as test results vary slightly with posture.

[0038] Two Finger Palpating Technique (FIGS. 10/12):

[0039] Face the patient with your fingers over the shunt valve and thumbpointing downstream in the distal direction. You may also reach acrossthe patient's head, as long as your thumb points distally. If you arethe patient performing this on yourself, use the hand on the same sideof your body as the shunt. Again, make sure your thumb points distally.

[0040] Checking/Flushing CSF Flow in the Proximal Direction (FIGS.10/12):

[0041] With your hand in the proper position, feel the shunt reservoirdome with your middle finger. Your index finger should be over thedistal side of the shunt. Carefully press down on the distal occluderwith your index finger “as though you were squashing a bug,” and hold itdepressed while gently depressing and releasing the reservoir using anisolated finger motion. Depressing the reservoir dome without pinchingoff the occluder will not allow an accurate reading of proximalresistance. Repeat this several times and note its firmness andresilience. Record the reservoir findings on the work page of FIG. 3under “Proximal” by circling the value that best describes your finding.Be sure to fill in the appropriate sample number.

[0042] To flush the shunt valve proximally, completely depress (do notforce) the reservoir with your middle finger while the above-notedoccluder is pinched off, and then release both fingers. Scoring: −2=verysoft, feels empty, may or may not refill properly into the reservoir;−1=softer than normal, very fluid, may refill properly; N=Normalfunction and feel; +1=rather firm, fuller than normal, increasedresistance to depressing, may refill slowly, normally or briskly;+2=very firm, may not be able to depress down, refills slowly orbriskly.

[0043] Checking/Flushing CSF Flow in the Distal Direction: (FIGS. 9/11)

[0044] With your hand in the proper position, feel the shunt reservoirdome with your middle finger. Next, slide this middle finger over on tothe proximal (upstream) side of the shunt. Your index finger should nowbe directly over the reservoir dome. Press down on the proximal occluderwith your middle finger “as though you were squashing a bug,” and holdit depressed while very gently depressing and releasing the reservoir,using an isolated finger motion. Repeat several times and note itsfirmness and resilience. Identify its refill qualities. Record yourfindings under “Distal,” and “Refill,” respectively, by circling thevalues that best describes your findings. Be sure to fill in theappropriate sample number.

[0045] To flush the shunt valve distally, completely depress (do notforce) the reservoir with your index finger, while the above-notedoccluder is pinched off, and then release both fingers. Distal Scoringis the same as Proximal Assessment.

[0046] Refill Scoring: −2=very slow to unable to refill; −1=slow torefill, but does so within a couple seconds; N=normal; +1=refillsbriskly, fuller and faster than normal; +2=refills very quickly,reservoir likely very firm and difficult to depress.

[0047] Type 2 Method (In-Line flushing reservoir) (FIGS. 10/12):

[0048] Shunt valves that do not incorporate an integral shunt valve witha central reservoir and directional occluders will normally have anin-line flushing reservoir proximal to the valve. Such systems do notpermit directional flushing. This technique may be used with Type 1systems as well, though the results are not as thorough.

[0049] To perform the In-Line reservoir test, locate the flushingreservoir with your middle or index finger and position your otherfingers comfortably around the reservoir dome. Very gently depress downon the reservoir using an isolated finger motion, and note its firmness.Repeat this motion several times, allowing pauses in between and notingits refill qualities. Record your reservoir findings under “In-line,”and “Refill,” respectively, on the System work page. Be sure to circlethe appropriate sample values. In-Line Scoring: −2=very soft, feelsempty of fluid, may or may not refill properly; −1=softer than normal,very fluid, may depress and refill properly; N=Normal function and feel;+1=rather firm, harder than normal, increased resistance to depressing,may refill slowly, normally or briskly; +2=very firm, hard to depress,refills slowly, normally or briskly. Refill Scoring: −2=very slow to norefill; −1=slow to refill within seconds; N=normal; +1=refills briskly,fuller and faster than normal; +2=refills very quickly, reservoir likelyvery firm.

[0050] Step 4. Performing the Cognitive Test. The user selects acognitive test for the test profile during initial setup. Suggestedtests are listed below. The system will now prompt the user to perform acognitive test. The cognitive tests below are some of the examples oftest that can be used to gauge the memory and IQ functions of the testedpatient. The results should be based on what is considered normal orbelow normal for that patient. The user is encouraged to try severaldifferent tests. After identifying the cognitive state, circle the scorenumber under “Cognitive” that best describes your findings. Generally,cognitive changes cause an individual to become quiet. Scoring: −3=mostsevere, unable to talk or express ideas, stare, unable to perform anycognitive tests; −2=moderately severe, quiet, unable to find the rightwords or be aware of what's happening around them, poor performance oncognitive tests, very irritable, may have a stare; −1=mild deficit, lessactive, some speaking or memory difficulties, may initially think he/sheis OK, yet cognitive tests will be impaired; N=normal or good (for thatpatient). Typical Scoring for Ages 10 and Over: 5/5 (channels, objects,Words)=N; 4/5=N; 3/5=−1; 2/5=−1 to −2; 1/5=−2; and 0/5=−3.

[0051] Suggested Cognitive Tests:

[0052] a) TV Multiple Channel Test. Using a TV remote control (ifavailable), have the patient browse a number of channels. From these,pick 5 shows and watch each one for 15 to 30 seconds. Then, allowseveral minutes to pass and ask the patient to identify the fiveprograms, and corresponding channels if able. You may also query thepatient after a longer time interval. Compare the test result to thepatient's normal finding and equate it in terms of a score from N to −3and mark the score on the work page of FIG. 3. Score it according to ageand development.

[0053] b) Objects Recall. This test can be performed anywhere, even ononeself. Identify five or more objects within a room or setting. Usemore objects for higher developed patients. Allow several minutes toelapse and ask the patient to recall the objects. Compare this to thepatient's pre-established normal function, and equate it in terms of ascore from N to −3.

[0054] c) Spelling/Phone Numbers. Ask the patient to spell or recallspelling words that he/she would ordinarily know. Start with easierwords and go to more difficult words. Choose up to ten words or phonenumbers. Compare this to the patient's pre-established or normalfunction, and equate it in terms of a score from N to −3.

[0055] d) Counting Backwards. This test can be started from the numbers100, 50, 1000, etc. The objective is to have the patient countbackwards. Having the patient count backwards and subtract by 3, 7 or asimilar number may increase the level of difficulty. The difficultylevel can also be adjusted to age and level of the patient by alteringthe complexity of the numbers, and by timing of the interval. Compareyour findings to the patient's pre-established normal, and equate it interms of a score from N to −3.

[0056] e) Equipment/Game Operation. Pick one of several games or piecesof equipment around the home or office that the patient knows how tooperate. Have the patient demonstrate the game or equipment operation.This tests concentration and recall. Suggested tests include computerprograms, popular games, televisions, VCRs, etc.. Compare this to thepatient's normal or pre-established function, and equate it in terms ofa score from N to −3.

[0057] Step 5. Performing the Positional Test. Make sure you have firstrecorded the Nausea, Cognitive, and Headache data on the work page. Thepatient should already be in a Supine (flat on back) or near Supineposition. Next, place the patient in the opposite postural position for1 to 3 minutes, or until he/she notes a change in the describedcomplaints. Circle a score on the work page according to the scoringbelow.

[0058] Opposite postural positions include a change from lying flat tositting or standing, standing to lying at a 30-degree upright angle, anda 30-degree upright angle to the Trendelenburg (30-degree head downward)position. If the patient experiences any intolerable worsening ofhis/her complaints, abandon the posture. Scoring: N (for No Complaints),↓ for Worsening Complaints, NC for No Change in Complaints, or ↑ forImproving Complaints, under the respective “Supine” or “Upright” columncorresponding to the posture. An N score would specify a patient withoutcomplaints. An NC score would specify an indeterminate result, unchangedby posture.

[0059] Next, place the patient in the opposite posture and maintain thatfor 1 to 3 minutes, or until a change is noted in the describedcomplaints. Circle either N, ↑, NC, or ↓ under the respective “Supine”or “Upright” column. Be sure to circle the appropriate sample.

[0060] In the event a NC (indeterminate) score is found, the user mayelect to do either of the following: 1) Allow up to ten minutes of timeto elapse in the measured postures; or 2) Use the Trendelenburg position(30-degree head down) in place of the Supine position.

[0061] The scientific merit in the Positional Test follows that ICP willbe higher when lying down, and lower when upright. In shunt malfunctioncases where there is increased ICP, the patient should feel worse lyingdown, and improved when upright. Conversely, in low ICP malfunctionssuch as over-drainage, the patient would feel improved lying down, andworse when upright. Headache (HA) is the most common outward barometerof ICP change, and widely used in hydrocephalus assessment.Nevertheless, some patients will exhibit nausea, vomiting, or cognitivechange more readily than headache.

[0062] In addition to the parameters mentioned above other conditionscan be observed. Some of those additional conditions are eye signs,balance, proximal refill, and distal refill.

[0063] The data gathered by the user is stored in a journal in additionto being passed on to the processing module. Recording the data in ajournal allows the system to later use the raw unprocessed data ingraphs and more advanced diagnosis tools such the pattern recognitionlogic discussed below. The user can additionally review the sample dataand modify measurements that are erroneous.

[0064] DiaCeph™ Processing

[0065] The following description relates to the processing of thesampled values to produce a set of predictions or evaluations. Theprocessor disclosed is a slide ruler processor using tables and forms.The DiaCeph™ Slide Chart Processor allows for analyzing the work pagedata, determining ICP, and plotting the ICP results on a Day-Chart. Theprocessor employs an “algorithm” relationship to the data. All possible“what if” scenarios are matched. Future additions or changes can be donesimply by changing the Answer Cards. The exact relations of the sampledata to a diagnosis can be determined in several manners. Onepossibility is to conduct clinical trails during which patients areobserved and diagnosed by invasive methods such as those used inhospital monitoring. Another manner by which the correlation of sampledata to the diagnosis can be accomplished is setting a single standardpredefined correlation. The diagnosis can be a deviation from thatstandard correlation resulting from an averaging of the first fewsamples. In this second method a normalized result is first achieved andthe sampling is later used to determine whether the shunt is deviatingfrom normal performance. The computerized version of the processor willincorporate the correlation file and automatically generate a diagnosisbased on sample data.

[0066] Template One (FIG. 5)

[0067] Step 1. Positional Value Key Column:

[0068] Positional Value is a middle equation value for analyzing +, −,N, or /N (indeterminate) postural changes in the Positional Test. Locatethe work page insert (FIG. 3). Find the Positional Value data column onthe lower left-hand side of the work page. It lists four (4) possibleValues, −, +, N, /N. Find the Positional Value Key in the upperleft-hand corner of Template One. Read the Positional Value by matchingthe Positional Test results of the sample to one of the six (6) lines inthe Key. Circle the Positional Value result for the sample underPositional Value on the work page (lower left).

[0069] Step 2. Determining ICP Value:

[0070] ICP, or intracranial pressure, is very important in determiningthe nature of a shunt malfunction. The normal medical practice fordetermining ICP is with a direct needle manometer reading through theshunt reservoir, which carries some risk. CT and MRI evaluation ofventricular size is most routinely used to measure a change in ICP, yetis an indirect sampling method.

[0071] To determine ICP, Set the Slide Chart in Window (A) to theCognitive and Headache scores from the work page. Align them with eachother on the slide, and then read the resulting ICP Value directly belowthe patient's Nausea score in either Window (B), (C), (D), or (E),depending on the Positional Value reading from Step 1. Circle this ICPValue under the ICP Value column on the work page.

[0072] The ICP processor function is scientifically based on theinter-relationship between nausea, headache, and cognitive changes whichfollows ICP change. In the shunted patient, adverse ICP changes arebrought on by a malfunctioning or improperly matched shunt system, or bychanges in the patient's posture. In the DiaCeph™ ICP processor, forexample, the more severe the headache in association with a supinepostural position, and accompanied by nausea and/or cognitive change,the higher the approximate ICP Value. Due to the methodology inobtaining this non-invasive data, there is a small “indeterminate” areain the /N range where ICP change is either too subtle to register, or ismasked by other occurring pathology. To help offset these possibleerrors, the ICP value is matched with the patient's Shunt SystemAnalysis in Template Three, and inconsistent values tend to be isolated.Additionally the barometric pressure can be measured to further refinethe ICP estimate thereby preventing barometric pressure variations fromaltering the estimate.

[0073] Template Two (FIG. 6):

[0074] Step 3. Reservoir Finger Test Analysis:

[0075] This step evaluates the Shunt Reservoir Finger Test data. Thetemplate provides results in “Letter Coding” of commonly foundconditions and Types of Shunt Malfunction (FIG. 13). Locate theReservoir Test scores for the sample and Set the slide so that theDistal score is aligned with the set the Refill score at the In-Linescore.

[0076] Step 4. Refill Score:

[0077] In Window (G), and without moving the slide, identify the Refillscore for the sample in the left-hand column in the box (Type 1Systems). Read the Coded Answer or match that appears in the window onthe same line. Write the Letter Codes in the spaces provided on the workpage under the Reservoir Analysis column. For In-Line reservoir testdata (Type 2), read the Coded Answer in the window on the line next to“In-Line.”

[0078] Step 5. Shunt System Analysis:

[0079] In Window (H), Set the slide so that the Malfunctions groupingfrom Step 4 appears in the window. Identify the Shunt Tract finding fromthe work page in the Box adjacent to Window (I). Read the Coded Answeron that line which appears in the window. Write the Letter Codes in thespace on the work page under Shunt System Analysis.

[0080] Template Three (FIG. 7):

[0081] Step 6. Determining the DiaCeph™ Diagnosis:

[0082] Steps 6 and 7 match the patient's ICP Value determined in Step 2with the Shunt System Analysis just concluded. The results are providedin Letter Codes. In Window (J), Set the Slide Chart so that the arrowabove the window is aligned with the Shunt System Analysis Code resultfrom Step 5.

[0083] Step 7. Diagnosis:

[0084] In Window (K), and without moving the slide, identify the ICPValue from Step 2 in the Box to the left of the window. Read theDiaCeph™ Diagnosis match in the window on the line adjacent to the ICPValue. Circle the Letter Codes on the Key provided on the work pageunder DiaCeph™ Diagnosis.

[0085] The Standard DiaCeph™ Diagnosis is reached by matching thepatient's Shunt Reservoir Finger Test results and Shunt Tract exam(Steps 3, 4, 5) to their approximated ICP Value. DiaCeph™ exposes thedata to a large field of shunt conditions and malfunctions (Steps 6 and7). The concept is based on the fact that each shunt malfunctiondisplays a unique set of findings in the DiaCeph™ Test. When these aretracked, scored, and analyzed, they can be matched with specific shuntmalfunctions. Once the processing step is complete the user may beprompted to either end the testing, return to the main menu, continue tothe advanced portion of the test including interventions, or performanother set of tests to gather an additional sample.

[0086] In another embodiment, the processing of values observed can bemade dependent on past values by modifying the processing of sampledvalues in the DiaCeph™ processor. For example the method by which ICPpressure is estimated can vary in accordance with the previous two ICPevaluations. If the previous two evaluations showed an increase in ICPover time, the processing to estimate the next ICP may account for thattrend by increasing the weight given to the Nausea score in theprocessing.

[0087] Additionally outside conditions may influence the observations.By measuring conditions such as room temperature and barometricpressure, the processing can be more accurate. Therefore, the DiaCeph™processor may also include an entry for the temperature and barometricpressure.

[0088] DiaCeph™ ICP Day-Chart (FIG. 4)

[0089] The Day-Chart plots the data, for example ICP Values determinedfrom DiaCeph's analysis of the patient's Nausea, Headache, Cognitive,and Positional Value scores, as a function of time. The data forplotting is taken from the journal. For example the resulting graph ofFIG. 4 provides a display of the patient's rising and falling ICP ashe/she undertakes various activities. By comparing an incident graph tothe patient's normal, even the most episodic shunt malfunction becomesclearer. The normals for each graph will vary according to the type ofshunt system and hydrocephalus pathology. Each patient shouldpre-establish a normal Day-Chart so as to permit informative comparisonto an incident graph.

[0090] The graph of, for example, the ICP values may be compared to apredefined set of deviations from a normal values for a specificincident or malfunction. DiaCeph™ can include a processor to correlate apredefined sets of deviations, relating to a specific incident, to thecurrent set of measurements. This correlation can be accomplished by,for example, storing a ten value set for each incident. The last tenobservations of a patient can be compared to the multiple sets of valuesby calculating the aggregate difference between the elements of thecurrent set with the elements of the stored sets. The stored set forwhich the aggregate difference is the least is the closest to thecurrent set. Therefore the processor will generate the diagnosis as theincident for which the set closest to the current set. The comparison tothe predefined sets can be done for each observed condition data or forthe entire set of observed conditions.

[0091] As a stand-alone single observed condition, for example ICPvalue, the comparison would follow the steps outlined above. Thediagnosis can be made more accurate at times, if more than one measuredcondition data is correlated to a predefined set. For example, a set ofdata over time, in the form of values such as ICP, reservoir analysisscore, refill score, can be stored for a given incident. The data from asample of those same observable conditions can be compared to the setsof values for a given incident by following the same procedure outlinedabove for the single data set. A correlation will be concluded if theaggregate differences between the observed set and an incident data isless than that for the other incidents. In this manner more than oneobservable condition is evaluated in determining whether an incidentcorresponds to a set of measurements over time. A more refined analysiscan be made by evaluating the relationship of the stored incident datato more than one observable condition. Alternatively the data can beplotted against time and manually compared to predefined graphs forcertain incidents.

[0092] Advanced DiaCeph™ Test (Interventions)

[0093] DiaCeph™ Interventions are an advanced segment of the DiaCeph™Test. They entail shunt system manipulations that both isolate aspecific shunt malfunction and/or help treat its associated complaints.In certain cases, these Interventions can be used to remedy an ensuingshunt malfunction. However, due to their nature and under certaincircumstances, a neurosurgeon may advise against a specific DiaCeph™Intervention because of a possible risk of aggravating an ensuingmalfunction. There is some risk the Intervention could exacerbate thefailing or disconnected component. To address this issue, the SlideChart processor provides a “not recommended” key code in window (M) oftemplate three. When used according to the instructions, DiaCeph™Interventions are safe and effective to the shunted patient.

[0094] Template Three (FIG. 7):

[0095] Step 8. Determining the Interventions:

[0096] This step correlates specific Interventions, determined by theDiaCeph- processor, in assessing the complex hydrocephalus patient. Afew of the Interventions may be contraindicated under certaincircumstances. DiaCeph™ provides a “not recommended” Code Key to alertthe user to these occasions.

[0097] In Window (L), Set the Slide Chart so that the arrow above thewindow is aligned with the DiaCeph™ Diagnosis result from Step 7. InWindow (M), and without moving the slide, read the Interventions andMalfunctions Codes that appear in the window adjacent to “FirstPriority, Second Priority,” etc. in the box. Write these numbers andletters on the spaces provided on the work page under Interventions.

[0098] Step 9. Performing Interventions:

[0099] Start with those Interventions marked “First Priority” in Window(M). After performing the Intervention, assess the patient's Status bydetermining if there has been any change in his/her complaints. Baseyour assessment on substantive changes in Nausea, Headache, and/orCognitive complaints. Headache is accepted as the most measurablecomplaint in hydrocephalus assessment, but it can vary from patient topatient. See also discussion under Positional Testing. Circle yourfindings under the “Status” column on the work page.

[0100] The concept behind DiaCeph™ Interventions (Advanced DiaCeph™Test) is to non-invasively challenge complicated shunt malfunctions, andreaffirm or reject a diagnosis. The Interventions are manipulations ofthe patient's body posture, his/her ICP pressures, and CNS shunt system.They are designed to result in known specific outcomes that coincidewith rising or falling ICP and specific shunt malfunction. The AdvancedDiaCeph™ Test has been shown to remedy some common shunt complaints. Itserves to assist the neurosurgeon in determining subsequent clinicaltesting and/or surgery.

[0101] On Template Three of the Slide Chart, in Window (L), there areMalfunction Codes and groups displayed across the middle section of theanswer card, which are based on the possible matches in Step 7, Window(K). Beneath this window, in Window (M), are columns of the MalfunctionCode/groups, each having rows of matching Interventions and counterpartLetter Codes, and one row of “Not Recommended” Codes. The followinginterventions are an example of some of the procedures that may berecommended by reference to the malfunction code/group determined by theprocessing steps:

[0102] 1. Lay Down and Rest: This simple method is for evaluating lowICP (over-drainage) versus increased ICP (under-drainage). Place thepatient flat (supine) for a period of several minutes to 15 minutes. Alow ICP state would find a noticeable improvement. An elevated ICP statewould find a worsening of the complaints lying down. Other pathologicalconditions could improve with rest, though unlikely improvement wouldoccur immediately.

[0103] 2. Lay Down to Trendelenburg: This position is described aslaying supine (on one's back) with the head tilted lower than the feetat an approximate thirty degree angle. This position is used fortreating and evaluating over-drainage. Lay in this position for 1 to 3minutes. Typically, either improvement or worsening will be seen almostimmediately, and the position can be abandoned.

[0104] 3. Exercise Activities: Exercise both raises a person's ICP, andcauses increased blood flow to the brain. In some cases, straining andincreasing ICP can improve CSF flow in a sluggish shunt system. It can,however, be harmful to a person with elevated ICP, as ICP will furtherincrease. In cases of over-drainage, exercise can purge and refreshstagnant venous blood flow caused by dilated vessels reacting to chronicover-drainage. Exercise has an additional positive hormonal effect uponthe brain by stimulating the release of endorphins and related chemicalsthat act to minimize pain and boost a feeling of well-being.

[0105] 4. Pinch off Shunt Occluder: Requires shunt valve with proximalor distal occluder. Have the patient assume a comfortable sitting orstanding position. Pinch off an occluder port with steady fingerpressure and hold for 1 to 3 minutes. Record the change in complaints.Over-drainage would reveal an improved level of complaints.Under-drainage would reveal no change, or a worsening level ofcomplaints.

[0106] 5. Close ASD Device: Occasionally, an ASD (anti-siphon device)mechanism will fail to retard CSF fluid in the upright posture, leavingthe patient over-draining with an otherwise lower pressure shunt. ThisIntervention requires the user to pinch off the proximal occluder anddepress the reservoir, hold the occluder pinched for 1 to 2 minutes.Alternatively, flush the shunt proximally several times.

[0107] 6. Assume an Upright Posture: This is effective in isolatingwhether complaints are due to shunt over-drainage or under-drainage. Italso brings relief to the latter condition. Under-drainage may berelated to a number of malfunction processes. Sit up or stand for 3 to10 minutes, and observe any change in condition.

[0108] 7. Flush Distally/Strain/Purge: Selective flushing can only beperformed on a shunt with central reservoir and proximal and distaloccluders. An in-line reservoir system normally flushes distally. In theevent of a distal obstruction, flushing may cause CSF fluid to flowproximally. Refer to the “flushing instructions” under the ShuntReservoir Finger Test. To flush, lay down in a supine up to a 30 degreeposition and perform 2 to 3 proximal flushes, followed by the samenumber of distal flushes. Repeat several times if desired. To purge,slowly tense up the body, hold and relax. Flush the shunt valve duringrelaxation. To use straining to assess ICP, lay supine to a 30 degreeangle and bear down (tense up) slowly and hold for several seconds, andrelax and repeat. If ICP is already elevated, straining will beuncomfortable and often not possible. If ICP is low, straining bringsrelief Straining increases ICP and blood flow within the brain and canbe harmful in cases of elevated ICP.

[0109] 8. Lift Up Overlying Scalp: In a supine, 30 degree or sittingposition, reach with the fingers of either hand to a spot 1 to 2 inchesbelow the shunt and push up on the scalp so as to create a loose (flap)pocket of scalp around the shunt. Hold this for 1 to 3 minutes. Thistest isolates overlying scalp pressure as a cause of upright ASD shuntover-function.

[0110] 9. Flush Valve Proximally: This requires a patient with a shuntwith central reservoir and proximal and distal occluders. Refer toflushing instructions under the Shunt Reservoir Finger Test. It is bestto lie in a reclined position. Pinch off the distal occluder, anddepress the reservoir with several finger depressions.

[0111] 10. Manipulate Abdomen/Shunt Tract: A disconnected component, ora mal-positioned peritoneal catheter, can prevent the required CSF flowfrom reaching its destination. Gently manipulate each suspect area toeffect a change in CSF flow through the shunt system. An improving orworsening level of complaints following this would suggest it is thecause of the shunt malfunction. In the case of a mal-positionedperitoneal catheter, repositioning may be accomplished by having thepatient take a breath as you manipulate the abdomen.

[0112] 11. Diamox Therapy: Diamox, or acetazolamide, is a specific typeof diuretic drug that has been found to reduce the rate of CSFproduction in the brain, thereby lowering one's ICP. The drop in CSFproduction, though not of any great amount, has its application thetreatment of hydrocephalus. It is commonly prescribed in the initialonset of hydrocephalus, and is used to relieve complaints associatedwith increased ICP due to intermittent shunt malfunction, and in generalcases of insufficient CSF outflow.

[0113] Diamox additionally has a diagnostic value. It can be used as anIntervention in the DiaCeph™ test in verifying the presence ofincreased, normal, or decreased ICP, as it slows CSF production andlowers ICP. The patient should take Diamox according to the times anddoses prescribed by their treating physician. An improvement incomplaints would be evidence of increased ICP; a no change in complaintswould indicate either very elevated ICP and/or other pathology; and aworsening in complaints would indicate either a low ICP condition, areaction to the Diamox, or too strong a dose.

[0114] 12. Elastic Wrap Over ASD: Placing an elastic wrap over an ASDshunt would, under normal circumstances, cause the shunt to open at a“higher” opening pressure, effectively reducing CSF outflow. An ASDdevice is one that has an anti-siphon membrane to prevent over-drainage.When external pressure is applied to the membrane, or a drop inhydrostatic pressure occurs, the flow of fluid is further inhibited. ASDdevices base their shunt opening pressure on a sensor below the scalpwhich is referenced to normal atmospheric pressure. Any increase inscalp pressure over this sensor would cause the device to open at ahigher opening pressure, thus elevating ICP.

[0115] These effects are very difficult to determine with routinetesting. Placing an elastic wrap over the ASD device has diagnosticimplications, by causing a patent shunt system to reduce CSF outflow,and measuring the resulting change in the patient's complaints. Aworsening of complaints would suggest responsive increase in ICP. Amatching of complaints to what was seen in a previous shunt malfunctionincident tends to confirm the suspected incident. An improvement incomplaints would suggest a low ICP condition, and shunt overdrainage atthat time.

[0116] Depending on the shunt malfunction that is being explored, thisIntervention could be used to mimic complaints caused by sleeping firmlyon the shunt, to confirm overlying scalp pressure as a cause of shuntinsufficiency, or to cause momentary relief in an ASD implanted patientsuspected of overdraining. This procedure should be performed by andonly according to the specific protocol of the treating physician.

[0117] Template Four (FIG. 8):

[0118] Step 10. Processing the Interventions:

[0119] Steps 10 and 11 enable the user to process post Interventionresults by aligning the slide arrow up with the Intervention results inWindow (N). Window (0) then provides the user with malfunction codesthat correspond to a match on the line adjacent to each malfunction. Inany given Intervention test, there may be one to several matches.

[0120] Since a few of the Interventions pose a small but measurable riskof injury to the shunt system, DiaCeph™ provides a “not recommended”code key also under Window (0) to alert the user to an Intervention thatcould be contraindicated. The user should also exercise good judgementin determining whether or not to perform a “NR” noted Intervention.

[0121] In Window (N), Set the Slide Chart so that the arrow below thewindow is aligned with the symbol results ↑, NC, or ↓ of theIntervention number being processed.

[0122] Step 11. Advanced DiaCeph™ Diagnosis:

[0123] In Window (O), and without moving the slide, read the MalfunctionCode Letter(s) which appear in the window. Read the Coded results whichappear on the same lines as the Malfunctions (listed at left) beingevaluated. A Malfunction code appearing in Window (O) represents anaffirmative match (diagnosis) with that malfunction, whereas a “−”symbol represents a rejection of that malfunction as a diagnosis. Apercent “%” symbol appearing in Window (0) adjacent to the malfunctiondenotes a possibility that the malfunction exists. Note any “NR” (notrecommended) Codes. Post the results to the work page by circling therespective Letter Code(s) under “Advanced Diagnosis.”

[0124] Continue performing the Interventions specified in Step 8, Window(M), until a single diagnosis has been reached, or all have beencompleted and the field cannot be further narrowed.

[0125] The results from applying the Interventions are based on currentscientific understanding of shunt systems, ICP needs and posturalchanges, and CSF flows.

[0126] By assigning various Number and Letter Codes to patient data,shunt conditions, malfunctions, and Slide Chart results, the AdvancedDiaCeph™ Test is able to handle as much as 390 possible shunt scenarios.

[0127] The procedure for sampling and processing the data can be madedependent on the shunt type observed. Since various shunt types can beused for patients, variations in shunt structure exist. Therefore, thesampling steps of the DiaCeph™ procedure should vary with the shunt typeobserved. This variation in sampling can be accomplished by, forexample, prompting the user to select a shunt type from a menu at thestart of testing when the procedure is implemented as a computer programor electronic device. The menu selection of shunt type will then affectthe sampling steps of the process by allowing for skipping certain stepsand performing others depending on the shunt type selected. In thismanner the DiaCeph procedure can be used by patients with various shunttypes without requiring the user to know which sampling procedure isrelevant to the specific shunt observed.

[0128] The DiaCeph™ processor can be implemented as an electronic dataprocessing device. With reference to FIG. 9, the device can be aspecially made unit that includes an input device 901, a processor unit902, a storage device 903, and a display 904. The processor unit 902 mayinclude memory and a signal processing chip. The processing unit 902 maybe a personal computer. The input device 901 can be a keyboard or a dataport. The storage device 903 may be a hard disk drive or a floppy disk.The display 904 may be any computer display screen. The DiaCeph™processor, in another alternative, can be wholly implemented as asoftware program. The program may include a routine to accept inputdata, a routine to process the data, and a routine to provide the datato some output device such as the computer display monitor. The programmay include a database file that is used by the processing routine. Thedatabase file may be updated from time to time as the correlationbetween input data and prediction is further refined.

[0129] Although the invention has been described in terms of certainpreferred embodiments, other embodiments that are apparent to those ofordinary skill in the art are also within the scope of this invention.Accordingly, the scope of the invention is intended to be defined by theclaims that follow.

What is claimed is:
 1. A data processing apparatus used to generate aprediction of CNS shunt operation, said apparatus comprising: an inputinterface; a disk drive; a display; and a processing unit to analyzesaid input data and generate output data corresponding to an identifierfor at least one prediction of shunt operation.
 2. A computer programused to process data to predict the operation of a CNS shunt comprising:a program module to receive data from a user; a program module toprocess said data and generate at least one prediction; and an outputmodule to pass said prediction to an output device.